AH01079: failed to make connection to backend: httpd-UDS

 

AWS 라이트세일을 운영하고 있는데 새벽에 서비스 접속이 안된다는 문의를 받음. 

 

확인해보니까 아래와 같은 503 에러가 발생하였음. 

 

Service Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

Additionally, a 503 Service Unavailable error was encountered while trying to use an ErrorDocument to handle the reque

 

AH01079: failed to make connection to backend: httpd-UDS

 

에러 로그 검색해보니 php-fpm 재시작하면 된다고 해서 아래와 같이 재시작해서 문제는 해결되었는데 

 

sudo /opt/bitnami/ctlscript.sh restart php-fpm

 

 

문제는 아파치 에러 로그에는 아래와 같이 새벽에 아파치에 shut down 명령어를 받았다고 나왔는데 그 시간대 부하로 보이는 것이 딱히 없는데 이런 현상이 발생했는지 모르겠다. 

 

AH00491: caught SIGTERM, shutting down

(Apache HTTP Server when it receives a SIGTERM signal, which is a signal that is used to request that a process terminate.)

[Sun Jan 01 02:00:03.261126 2023] [mpm_event:notice] AH00491: caught SIGTERM, shutting down
[Sun Jan 01 02:00:28.214995 2023] [ssl:warn] AH01882: Init: this version of mod_ssl was compiled against a newer library (OpenSSL 1.0.2s  28 May 2019, version currently loaded is OpenSSL 1.0.2r  26 Feb 2019) - may result in undefined or erroneous behavior
[Sun Jan 01 02:00:28.217621 2023] [ssl:warn] AH01909: localhost:443:0 server certificate does NOT include an ID which matches the server name
[Sun Jan 01 02:00:28.229128 2023] [ssl:warn] AH01882: Init: this version of mod_ssl was compiled against a newer library (OpenSSL 1.0.2s  28 May 2019, version currently loaded is OpenSSL 1.0.2r  26 Feb 2019) - may result in undefined or erroneous behavior
[Sun Jan 01 02:00:28.229845 2023] [ssl:warn] AH01909: localhost:443:0 server certificate does NOT include an ID which matches the server name
[Sun Jan 01 02:00:28.231461 2023] [mpm_event:notice] AH00489: Apache/2.4.39 (Unix) OpenSSL/1.0.2r configured -- resuming normal operations
[Sun Jan 01 02:00:28.231495 2023] [core:notice] AH00094: Command line: '/opt/bitnami/apache2/bin/httpd.bin -f /opt/bitnami/apache2/conf/httpd.conf -D DISABLE_BANNER'
[Sun Jan 01 02:00:29.243074 2023] [proxy:error] (111)Connection refused: AH02454: FCGI: attempt to connect to Unix domain socket /opt/bitnami/php/var/run/wordpress.sock (wordpress-fpm) failed